Changing ellipsoidal heights to geoid

Reach RS2 / RS2+ RTK / PPK configuration
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Hi,

i use Emild Reach Rs+ and Reach M+ and a Reference Station in Germany (Sapos Station) for Post processing of my GPS-Data.
After Post Processing i got all the Coordintes of Rover in WGS84. In our Project i musst change the Vertical system from Ellipsoidal in DHHN2016 (Height reference in Germany). Could you please help me? How can i change my vertical system?(From WGS 84 in DHHN 2016)

Thanks alot!

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Hi, Maryam!

You have to apply geodetic corrections to your data. As far, as I understood, you have to obtain the geoid model from here: https://www.bkg.bund.de/DE/Ueber-das-BKG/Geodaesie/Integrierter-Raumbezug/Hoehenbezugsflaeche/hoehenbezug.html . Then, you will need to recalculate your ellipsoidal heights to geoid. Usually, it is done by subtracting geoid undulations from ellipsoidal measurements. But, it depends on the model, you are using.

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Is it possible in Postprocessing with RTK-lib to change the vertical system ? or is it possible to change the Coordinate system via Reach View in Rover and Base?

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Coordinate systems are on a roadmap for development of the new versions of ReachView. For now, you can use some GIS software for calculations. I am not sure if you can do it in RTKlib. Usually I do it in GIS or in R.

2 Likes
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there is a option to enter a geoid in RTKLIB but i have not used it, but now that you mention it i shall look into it.

1 Like
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Hi,

I have written a script to do that automatically.
https://community.emlid.com/t/another-survey-post-processing-software

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How can i downlod and use it?

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Could you please give me EPSG code for Reference Coordinate system , which emlid uses? Is it EPSG:7789 ?

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Take a look at „webcaddy“ (www.caddy-geomatics.de)! I´m using ist with my rs2. You can survey and stackout with WGS84, UTM or GK Coordinatesystems and you get the hight in DHDN.

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Where I am in Canada, the National geomatics department of the government provides a free utility to transform elliptical heights to the national grid orthometric height using a selection of vertical datum and/or geoids. Perhaps the same is where you are located.

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2 posts were split to a new topic: Reach RS2 Datum

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Hi Maryam,

Could you please give me EPSG code for Reference Coordinate system , which emlid uses? Is it EPSG:7789 ?

Reach supports WGS84: EPSG4326 at the moment.

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I’m confused. Isn’t WGS84: EPSG4326

a horizontal datum? What vertical datum is used by RS2? What Ellipsoid model? I’m trying to use the NOAA Vdatum program to convert height above the Ellipsoid (that RS2 provides) to an orthometric height (height above the geoid = height above mean sea level).

David

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Reachview is using EGM96.

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